Table 1. Physicochemical characteristics of ALN-modified proteins.
| Compound | Number of ALN Residues (mol/mol) a) | Proportion of Modified Carboxyl Groups (%)a) | Number of PEG (mol/mol) b) | Estimated Molecular Weight c) | Isoelectric Point |
|---|---|---|---|---|---|
| GR | 0 | 0 | - | 112,000 | 4.5 |
| GR-ALN(4) | 3.79 | 1.11 | - | 113,000 | 8 |
| GR-ALN(17) | 17.3 | 5.06 | - | 117,000 | 8.3 |
| BSA | 0 | 0 | - | 67,000 | 4.8 |
| BSA-ALN (3) | 2.47 | 2.52 | - | 67,800 | 4.8 |
| BSA-ALN (28) | 27.7 | 28.3 | - | 74,600 | 9.5–10.7 |
| BSA-ALN (40) | 39.7 | 40.5 | - | 77,900 | >10.7 |
| SOD | 0 | 0 | - | 32,000 | 4.9 |
| SOD-ALN(3) | 2.99 | 7.88 | - | 32,800 | 4.9 |
| SOD-ALN(32) | 31.6 | 83.2 | - | 40,700 | 10.7 |
| PEG(10)-SOD | 0 | 0 | 9.62 | 82,000 | N.D. |
| PEG(10)-SOD-ALN(4) | 3.79 | 10 | 9.62 | 83,100 | N.D. |
| LZM | 0 | 0 | - | 14,000 | 11.2 |
| LZM-ALN(5) | 29.9 | 29.9 | - | 15,400 | N.D. |
| LZM-ALN(9) | 49.4 | 49.4 | - | 16,400 | N.D. |
a) The alendronate (ALN) content was determined by the molybdenum method using ALN as a standard. The number of ALN residues was calculated using the molar ratio of ALN residues attached to the protein.
b)The number of PEG was estimated by the number of unreacted free amino groups, which was determined by the trinitrobenzenesulfonic acid method.
c) The molecular weight of each protein derivative was estimated by considering of the number of ALN residues and PEG modifications.
N.D.; not determined